The way information is streamed from computer screens today does not match the way in which the human perception system is designed to handle information flow. Flow is poorly mapped to the human perception system. To use a “bus” analogy, humans have a 64-bit perception system, but the computer display is only 8 bits wide.
Computers began as tools and toys created by geeks, for geeks. There was no need for the vast majority of people to understand them, or even interact with them at all. Numbers or data were given to the data-processing department and you waited until you got a printout back. Computers did not have to be comprehensible by ordinary users
That all changing with the advent of the personal computer (PC). To make PCs acceptable, the PC had to be made much more approachable.
People have been talking for some time about how the PC is changing from a tool used to create data into a system for information consumption. Computers are still used to create information in the form of documents, email, spreadsheets, and databases, for example. But the growth of the Internet has made the computer a window on the world from which information is either streamed to the user or a channel that is used to go out and look for it.
People speak about the computer as an “Information Portal”. For many, the Internet has replaced newspapers, magazines, and TV as the place to go for news. That process will continue as information channels get better, as displays improve in quality, and electronic magazines and newspapers become as pleasant to read on screen as in paper.
However, in all this talk about the computer as an information portal, one important and fundamental fact has been neglected. Notwithstanding all of the advances in the user interface, it is not matched to the human perception system. The interface focuses all the information humans process into a channel that is far too narrow.
Instead of using all the attributes of human perception, i.e., foveal, parafoveal, peripheral vision, and 360-degree audio, information is being forced through the high-resolution (but narrow) foveal vision channel, which channel is now overloaded. Everything that takes place in foveal vision is a high-priority interrupt. Visual, precognitive triage is not possible. Attention must be given to all information that appears there.
Foveal vision is high-resolution vision that is used to focus on an object. The fovea is an area of the retina that is only about 0.2 mm across and has about 1.5 degrees of visual arc. The fovea facilitates foveal vision, which is an elliptical area just slightly less than an arms-length from the eyes. Objects are examined in this area, which is also the area used by humans to invent tools, to read, and to write.
The parafovea is the area of the retina immediately surrounding the fovea. This is a lower-resolution part of human vision whose major role appears to be to provide targeting information to determine the position of the next fixation, i.e., the length and direction of each successive saccade. Thus, the parafovea still plays a role in foveal vision, by targeting it effectively. Thought of in another way, it could be said that fovea and parafovea together make up a human high-resolution vision system. The resolution in the parafovea falls off gradually as the user moves farther away from the fovea.
The fovea/parafovea defines an ellipse that is approximately 12 inches high and 9 inches wide at a “normal reading distance” that ranges from about 2–22 inches.
The resolution of vision is highest in the fovea, then starts to drop off as the person moves further out in the parafovea. The drop is gradual at first, but accelerates dramatically, until out at the edges of the peripheral vision all that can be seen is movement.
Humans are incredibly sensitive to movement, especially at the periphery, using peripheral vision. Researchers have long reported that males and females use different strategies to navigate through the world. In broad terms, females use landmarks to navigate, while males tend to use broader bearings, such as direction of travel.
In two studies, it was found that a computer display with an ultra-wide field of view benefited both male and female users, and reduced the gender bias. Moreover, women took a wider field of view to achieve similar virtual environment navigation than men.
Without moving the head, humans can see about 208 degrees around in the periphery. Studies suggest how existing computer displays are biased towards male perception and fail to adequately use the peripheral vision. Thus, the 208-degree field of vision is not enough. To get full coverage, the person needs to be able to turn his or her head. To know when to turn the head, and to give coverage even when looking forward, sound is used.
Sound is a key piece of the human perception system. Sound processing provides additional coverage for those areas sight cannot cover. Sound covers all the areas outside vision up and towards the rear. It also allows humans to extend perception out beyond the range of vision, especially in areas where either growth or terrain create line-of-sight obstacles. Heretofore, sound in PC's has been used principally to create beeps. However, it has a lot more potential when analyzing the role it plays in the integrated perception of humans. There are some aspects of sound that should be considered as part of matching computer output to human perception input. Natural sound is “surround sound”. Human perception has a “sound stage” that extends 360 degrees. Sound has direction, which indicates where to focus sight. For example, “You've Got Mail-Here!” means much more than “You've Got Mail!” Sound from behind the user, especially sharp sound, is a high-priority interrupt. Sound helps the user to extend perception into areas that cannot be seen. In the modem world, events on the other side of the globe can affect the way business is conducted.
When reading a book, conscious attention may be totally absorbed in the book. Peripheral vision, however, is still scanning its area of coverage for interrupts. If anything moves within the field of vision, the movement will trigger attention and distract the user from reading.
That is one reason pop-up ads on web pages are so annoying—because of the distraction aspect. It is also the main reason advertisers use them—to distract the viewer from other content, and to their message. Pop-ups are annoying because they appear in the area of focus, and not the periphery. In nature, when focusing on something, the object of focus stays more or less stable; the major interrupt signals of movement take place in the peripheral vision. In contrast, web pop-ups are presented in the focal plane.
The separation of human perception into focal plane, peripheral vision, and audio input is important in understanding how personal computers have degraded the human information triage system over the past couple of decades. The computer screen, placed more or less at reading distance from the eyes, is clearly a “focal plane” device. With current screen sizes, it pretty well has no input to the peripheral vision. Yet PCs have been used to dramatically increase the amount of data streaming at the viewer. In effect, the flow of data has increased to the human perception system, while reducing its bandwidth.
There is a need for increasing the bandwidth available for information triage in the human perception system.